Supporting multiple mats

ABSTRACT

A support structure for retaining a reinforcing bar (“rebar”) in stacked layers. Such a structure includes a first support structure retaining a first rebar for a first mat. The support structure further includes a second support structure retaining a second rebar for a second mat. The first support structure and the second support structure can have similar configurations. The second support structure includes a first layer engaging portion, a second layer engaging portion and a support portion for connecting said engaging portions. The second layer engaging portion may include a reinforcing receptacle which includes a channel open to receive a rebar. The channel is defined by sidewalls that extend radially outward from an inner end receptacle. The sidewalls spread so that the rebar can pass retaining features on the walls of the channel and rest in a bar retaining portion as the rebar moves down the channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to the following commonly owned co-pending U.S. Patent Application:

Provisional Application Ser. No. 61/309,788, “System and Method of Supporting Multiple Mats,” filed Mar. 2, 2010, and claims the benefit of its earlier filing date under 35 U.S.C. §119(e).

TECHNICAL FIELD

The present invention relates to reinforcing bars (“rebars”) used in construction, and more particularly to retaining a rebar, a wire mesh, an electrical conduit, plumbing or other elongated bar in a desired configuration during construction.

BACKGROUND

Concrete is commonly used as a construction material because of its relatively low cost. Concrete is very strong in compression, but weak in tension. To increase the tensile strength of concrete, steel reinforcement bars (“rebars”) are added. For foundations, road work or other flat constructions, the rebar is often laid out in a grid pattern beneath the surface of the construction. To hold the rebar together in a grid, the bars are tied together where they intersect.

Various codes specify where the rebar must be placed. For example, the American Concrete Institute (ACI) in Section 318 of their code specifies that the rebar in a slab-on-grade foundation must be placed at the midpoint depth of the foundation. Thus, for example, in a four inch foundation slab, the rebar grid would normally be placed at a depth of approximately two inches. Consequently, the grid must be elevated off the ground to the desired position before concrete is poured. In many cases, concrete laborers use stones, pieces of broken bricks or materials to elevate the grid. This can cause the grid to be uneven or sag when the concrete is poured.

For concrete pillars and beams, the rebar is tied to a set of wooden frames and placed in a mold. The concrete is then poured into the mold to form the pillar, beam or other construction. However, this method suffers many disadvantages. First, it is difficult to align the rebar in parallel around the frames. Second, the frames often break or shift when the concrete is poured, causing the rebar to become misaligned. This reduces the tensile strength of the construction.

BRIEF SUMMARY

In one embodiment of the present invention, a support structure for retaining a reinforcing bar in stacked layers comprises a first support structure retaining a first reinforcing bar for a first mat. The support structure further comprises a second support structure retaining a second reinforcing bar for a second mat, where the second support structure comprises a first layer engaging portion, where the first layer engaging portion comprises one or more reinforcing bar receptacles. Furthermore, the second support structure comprises a second layer engaging portion, where the second layer engaging portion comprises one or more reinforcing receptacles sized to fit the second reinforcing bar for the second mat. One of the one or more reinforcing receptacles comprises a channel open to receive the second reinforcing bar, where the channel comprises a first portion open to the top of the second support structure and a bar retaining portion. The channel is defined by sidewalls that extend radially outward from an inner end receptacle of the one or more reinforcing receptacles. Retaining features are disposed on the walls of the channel so that a width of an opening to the bar retaining area is smaller than a width of the bar retaining area, where the sidewalls spread so that the second reinforcing bar can pass the retaining features and rest in the bar retaining portion as the reinforcing bar moves down the channel. In addition, the second support structure comprises a support portion connecting the first layer engaging portion and the second layer engaging portion, where the support portion comprises legs that support the second layer engaging portion and provides an offset from the first layer engaging portion.

The foregoing has outlined rather generally the features and technical advantages of one or more embodiments of the present invention in order that the detailed description of the present invention that follows may be better understood. Additional features and advantages of the present invention will be described hereinafter which may form the subject of the claims of the present invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A better understanding of the present invention can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:

FIG. 1 illustrates an embodiment of the present invention of retaining rebar in stacked layers;

FIG. 2 illustrates an embodiment of the present invention of a support structure;

FIG. 3 illustrates another view of the support structure in accordance with an embodiment of the present invention;

FIGS. 4A-4E illustrate various embodiments of the present invention of retaining features;

FIG. 5 illustrates a set of support structures supporting layers of bars in accordance with an embodiment of the present invention;

FIG. 6 illustrates one embodiment of the present invention of structurally tying together various layers used in construction;

FIG. 7 is a flowchart of a method for laying out rebar according to an embodiment of the present invention;

FIG. 8 illustrates another embodiment of the present invention of a support structure; and

FIGS. 9A-9D illustrate various embodiments of the present invention of a leg engaging a leg receptacle.

DETAILED DESCRIPTION

Embodiments described herein provide systems for retaining a rebar, a wire mesh, an electrical conduit, plumbing or other elongated rod in a desired configuration during construction. Embodiments described herein will be described primarily in the context of rebar, but it should be understood that the embodiments are not limited to rebar and can be used to retain other types of bars.

Embodiments described herein allow multiple layers of rebar and other materials to be linked together to provide stability during construction. According to one embodiment, different layers or ‘mats” of rebar are linked together. Embodiments of the present invention cover any number of layers or mats of rebar which may be linked together. In other embodiments, a layer of electrical conduit is linked to a layer of plumbing that is linked to a layer of rebar. In other embodiments, multiple types of rods can be used in the same layer (e.g., a layer having electrical conduit and plumbing, a layer having rebar and electrical conduit, etc.). Other combinations of layers can be used.

FIG. 1 is a diagrammatic representation of one embodiment of the present invention for retaining rebar in stacked layers. FIG. 1 illustrates an embodiment of a first rebar support structure 100 and a multi-layer rebar support structure 102. Rebar support structure 100 retains rebar 104 for a first mat while support structure 102 retains rebar 106 in a second mat. As shown in FIG. 1, structures 100 and 102 can have similar configurations. In other embodiments, the first rebar support structure 100 can be a rebar chair as described in U.S. Pat. No. 6,282,860, which is hereby fully incorporated by reference herein, support structures described in U.S. Provisional Patent Application No. 61/309,787, entitled “System and Method of Supporting Rebar With Interchangeable Crowns,” filed on Mar. 2, 2010, which is hereby fully incorporated by reference herein, or other rebar support structure.

Support structure 102 comprises a first layer engaging portion 110, a second layer engaging portion 112 and a support portion 114 connecting the first layer engaging portion 110 and the second layer engaging portion 112. According to one embodiment, support structure 102 is formed of a unitary piece of resilient plastic and does not require ties or caps to retain the rebar. Support structures can be manufactured to surpass requirements from the Uniform Building Code, International Building Code, American Concrete Institute, American Association of State Highway and Transportation Officials and standard practices as specified by the American Concrete institute and the Concrete Reinforcing Steel Institute and other standards. According to one embodiment, support structures 102 can be manufactured to have a capacity exceeding expected construction loads, which typically range between 250-300 pounds. Support structures 102, according to one embodiment, can have a critical load in axial compression of 320 pounds or more. According to one embodiment, support structures 102 can have a critical load in axial compression of approximately 400 pounds. Other embodiments can have higher or lower critical loads as needed or desired.

FIG. 2 is a diagrammatic representation of one embodiment of the present invention of support structure 102 having a first layer engaging portion 110, a second layer engaging portion 112 and a support portion 114. FIG. 3 is a diagrammatic representation illustrating another view of support structure 102 in accordance with an embodiment of the present invention. Returning to FIG. 2, first layer engaging portion 110 includes rebar receptacles 115, 116, 117 and 118 (each indicated receptacle can have a corresponding paired receptacle (e.g., receptacle 115 is paired with receptacle 115′). Each rebar receptacle can be sized to accommodate a particular size or range of sizes of rebar. Second layer engaging portion can 112 can include rebar receptacles 120, 122, 124 and 126 sized to fit the rebar of the second mat (each indicated receptacle can have a corresponding paired receptacle (e.g., receptacle 120 is paired with receptacle 120′)). Support portion 114 can include legs 119 that support second layer engaging portion 112 and provide an offset from first layer engaging portion 110.

The rebar receptacles of first layer engaging portion 110 and second layer engaging portion 112 can be configured to retain the rebar. Using the example of rebar receptacle 124, the rebar receptacle can include a channel 130 open to receive the rebar from a second direction. Channel 130 can have a first portion 138 open to the top of structure 102 and a bar retaining portion 139. Receptacle 124 can be open in the opposite direction of, for example, receptacle 117. Channel 130 can be defined by sidewalls 132 that extend radially outward from an inner end of receptacle 124. According to one embodiment, sidewalls 132 can be angled so that the width of channel 130 decreases from the opening to the base of channel 130. The base of channel 130 can have a flat shape, curved or other shape to cup the rebar. A curved shape can increase the lateral elasticity of receptacle 124.

Retaining features 137 can be disposed on the walls of channel 130. In one embodiment, retaining features 137 can be a bumps or other feature so that the width of the opening to bar retaining area 139 is smaller than the width of bar retaining area 139 or the rebar. In various embodiments, retaining features 137 can be formed based on the shape of sidewalls 132, can be projections that project inward from sidewall 132 or can be other features that allow the rebar to enter rebar retaining area 139 due to the pressure of the rebar, but inhibit the rebar from leaving bar retaining area 139.

The receptacles can be joined to each other by arms 121. According to one embodiment, the sidewalls of the receptacles and arms can be formed by a continuous, unitary shaped rib of material that projects radially outward from a first edge near the center of rebar engaging portion 112. The rib can be laid out in an annular shape with an opening or gap between paired receptacles. Thus, each receptacle, according to one embodiment, does not extend to the base of the paired receptacle (e.g., the base of receptacle 121 across engaging portion 112 to the base of receptacle 120). Instead, there may be a gap between the paired receptacles at the center of bar engaging portion 112.

In operation, the rebar can enter a first portion 138 of channel 130. As the rebar moves down channel 130, sidewalls 132 can spread slightly so that the rebar can pass bumps 137 and rest in bar retaining portion 139. According to one embodiment, bumps 137 snap over the rebar to inhibit the bar from coming out of channel 124. The material, thickness or other properties of sidewalls 132 can be selected so that the rebar can be inserted into support structure 102 manually. The other receptacles of the second layer engaging portion 112 can have a similar configuration and can be sized to receive the same or different sizes of rebar. The receptacles can have the same width or different widths. According to one embodiment, each pair of receptacles can have a different depth so that the rebar of the second layer can cross.

Bar receptacles 115, 116, 117 and 118 can have a similar configuration as the bar receptacles of second layer engaging portion 112. In other embodiments, bar receptacles 115, 116, 117 and 118 do not retain the bar, but simply rest on the lower layer of rebar. While eight receptacles are shown to accommodate four different sizes of rebar in each layer, first layer engaging portion 110 and second layer engaging portion 112 can comprise any number of receptacles sized to engage any number and size pieces of rebar. The receptacles can be positioned to engage rebar at various angles.

First layer engaging portion 110 and second layer engaging portion 112 can be configured to accommodate the same size rebar or different sizes of rebar. If the same size of rebar is used, the first layer engaging portion 110 and second layer engaging portion 112 can be configured so the rebar of the same size in each layer is in the same orientation or in different orientations. First layer engaging portion 110 and second layer engaging portion 112 can accommodate the same number of bars or different number of bars. By way of example, but not limitation, first layer engaging portion 110 can be configured to accommodate the rebar in a grid while second layer engaging portion 112 can be configured to retain a single piece of rebar. Additionally, first layer engaging portion 110 and second layer engaging portion 112 can be configured so that the rebar of the first layer is laid out in a first set of directions while the rebar in the second layer is laid out in a different set of directions. Thus, for example, a grid of the first layer may be at 45 degrees (or other angle) from the grid of the second layer.

Support portion 114 can include a set of legs 119 running from first layer engaging portion 110 to second layer engaging portion 112. According to one embodiment, a leg may run from the bottom of a receptacle of second layer engaging portion 112 to the top of a receptacle of first layer engaging portion 110. Legs 119 may angle outward because first layer engaging portion 110 can be wider than second layer engaging portion 112 to provide a wider base and to allow for stacking of support structures 102 in a column (see FIG. 1).

While various embodiments illustrated show eight legs, other embodiments can have more or fewer legs. Support portion 114 can include any number of legs 119 that can have various configurations. According to one embodiment, legs 119 can be shaped so that concrete can flow between legs 119 into a generally open area 140 between first layer engaging portion 110 and the second layer engaging portion 112. Various portions of support structure 102 can include holes (e.g., circular, diamond, triangular, rectangular or other shaped holes) to reduce material and/or allow for flow of concrete.

FIGS. 4A-4E illustrate various embodiments of retaining features 137 including a tapered flange (FIG. 4A), rounded flange (FIG. 4B), a set of teeth (FIG. 4 c) and a set of bumps (FIG. 4D). It should be noted that the embodiments of FIGS. 4A-4D are provided by way example. While each embodiment of FIGS. 4A-4D includes a taper or curve to ease insertion of the rebar, other embodiments of retaining features 137 can have other configurations. Retaining features 137 may be disposed on both sidewalls or only one sidewall and multiple types of retaining features can be used. Similar retaining features can be used for the retaining features of lower layer engaging portion 110. In one embodiment, the snap fit provided by a bar receptacle can be based, in part, on deformation of retaining features 137. In FIG. 4E, the rebar can enter the receptacle in a first direction and snap in a second direction.

FIG. 5 is a diagrammatic representation of a set of support structures 102 supporting layers (referred to as “mats”) of bars in accordance with an embodiment of the present invention. In the embodiment of FIG. 5, the various mats are cross-linked by supporting structures 102. While both mat 170 (represented by solid lines) and mat 172 (represented by dashed lines) can be grids of rebar, in other embodiments, mat 170 can be a grid of rebar, while mat 172 includes plumbing, electrical conduit or other material. Support structures 102 can be arranged in columns or be offset from each other. Support structures 102 may have a variety of heights to achieve desired separation between layers 170 and 172. In some cases, the separation between layers may vary at different points. Concrete can be poured around the layers to create a construction.

FIG. 6 is a diagrammatic representation of one embodiment of the present invention of structurally tying together various layers used in construction, including layers 180, 182, 184 and 186. Each layer can include one or more of rebar, plumbing, electrical conduit or other bars that can be accommodated. According to one embodiment, plastic cross-links 187 can form columns 188 to cross-link the layers. In another embodiment, plastic cross-links 187 can be offset from each other (as shown for example by cross-link 187′ offset from the other cross-links). Plastic cross-links 187 can be placed as needed or desired. Plastic cross-links 187 can have a variety of configurations and heights to achieve desired support and separation between layers 180, 182, 184 and 186. In some cases, the separation between layers may vary at different points. According to one embodiment, plastic cross-links 187 can be support structures 102 as described above. Concrete can be poured around the layers to create a construction.

FIG. 7 is a flowchart of a method 700 for laying out rebar according to the present disclosure. The rebar for an upper and lower rebar mat can be selected (step 200). The first rebar mat can be laid out (step 202) using traditional tie on methods, rebar support structures 100, rebar supports described in U.S. Pat. No. 6,282,860, which is hereby fully incorporated by reference herein, rebar support structures described in U.S. Provisional Patent Application No. 61/309,787, entitled “System and Method of Supporting Rebar With Interchangeable Crowns,” filed on Mar. 2, 2010, which is hereby fully incorporated by reference herein, or other rebar support structure. Based on the size of rebar in the first mat, size of rebar in the second mat and desired separation distance, multi-layer support structures can be selected (step 204) and secured to the first rebar mat (step 206). The following Table 1 provides example combinations of rebar and separation distances. However, other configurations can be used as needed or desired:

Application Distance from Grade/Height #3 rebar over #3 rebar #4rebar over #4 From 2.0 to 6.0 inches, Center- rebar #5 rebar over #5 rebar to-Center Mat Distance #4 rebar over #4 rebar #5 rebar over #4 rebar #5 rebar over # 3 rebar #6 rebar over #6 rebar #7rebar over #7 From 2.5 to 6.0 inches, Center- rebar to-Center Mat Distance #7Tehar-over#6-mbar #6 rebar over #5 rebar #7 rebar over #5 rebar #7 rebar over #7 rebar #8rebar over #8 From 3.0 to 6.0 inches, Center- rebar to-Center Mat Distance #8 rebar over #7 rebar #7rebar over #6 rebar #8 rebar over #6 rebar

Table 1 assumes the first mat and second mat are grids having the same types of rebar. However, in other embodiments, the first and second mats can have different combinations of rebar.

According to one embodiment, the multilayer support structures can be secured to the first mat with a snap-on feature. Rebar for the second mat can be secured to the multilayer support structures (step 208). Again, the rebar can be secured to the multilayer support structures with a snap-on feature.

Rebar running in one direction can be laid down first and then rebar running in a second direction. For both mats, the larger rebar can be locked across the smaller rebar or vice versa. The steps of FIG. 7 can be repeated as needed or desired.

FIG. 8 is a diagrammatic representation of another embodiment of the present invention of a support structure 102. In the embodiment of FIG. 8, first layer engaging portion 110 and second layer engaging portion 112 can be detached. Legs 119 extending down from second layer engaging portion 112 can be received by foot receptacles 152 on first layer engaging portion 110. According to one embodiment, foot receptacles 152 can be disposed on the top of portion of the bar receptacles of first layer engaging portion 110. In another embodiment, as shown in FIG. 8, foot receptacles 152 can be disposed on a platform 154 so that all the foot receptacles are at the same height.

FIGS. 9A-9D are diagrammatic representations of various embodiments of the present invention of a leg 119 engaging a leg receptacle 152. The retaining feature to retain leg 119 in receptacle 152 can be configured so that leg 119 cannot be removed without damaging receptacle 152 or leg 119 or can be configured so that leg 119 can be removed without causing damage if a threshold amount of force is applied. According to one embodiment, receptacle 152 can have sidewalls 154 that flex outward as leg 119 is inserted.

Complementary engaging features on sidewalls 154 and leg 119 can engage to hold leg 119 in place. In FIG. 9A, leg 119 includes an indent 156 that engages a detent 158 on wall 154 of receptacle 152. The resiliency of walls 154 can hold detent 158 in indent 156 so that a threshold amount of force is required to disengage leg 119 from receptacle 152. In FIG. 9B, flanges 160 on walls 154 move over shoulders 162 on leg 119 to hold leg 119 in receptacle 152. In FIG. 9C, a tab 165 on leg 119 is received in a complementary receiver in sidewall 154. In FIG. 9D, bumps 166 fit over a portion of leg 119 to inhibit removal of leg 119. The examples of FIGS. 5A-5D are provided by way of example and other engaging features can be used. In other embodiments, leg 119 and sidewalls 154 can form an interference fit based on sizing.

In various embodiments discussed above, both the first layer engaging portion 110 and second layer engaging portion 112 can use a snap-on to retain rebar. In other embodiments, only one of the first or second rebar engaging portions are snap-on. The other portion can require ties, caps or additional materials to secure the rebar. For example, one embodiment can use a snap-on first layer engaging portion while the second layer engaging portion retains the rebar using a head similar to the chair employed by the Hardy Chair-Lok system by Edgeworth Construction Products, LLC (Hardy Chair-Lok is a trademark of Edgeworth Construction Products, LLC of Houston, Tex.) or other rebar support chair known or developed in the art.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead these examples or illustrations are to be regarded as being described with respect to one particular embodiment and as illustrative only. Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized encompass other embodiments as well as implementations and adaptations thereof which may or may not be given therewith or elsewhere in the specification and all such embodiments are intended to be included within the scope of that term or terms. Language designating such non-limiting examples and illustrations includes, but is not limited to: “for example,” “for instance,” “e.g.,” “in one embodiment,” and the like.

Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the disclosure. It is to be understood that the forms of the disclosure shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the disclosure may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Any dimensions provided are provided by way of example only and not limitation. Changes may be made in the elements described herein without departing from the spirit and scope of the disclosure. 

1. A support structure for retaining a reinforcing bar in stacked layers comprising: a first support structure retaining a first reinforcing bar for a first mat; and a second support structure retaining a second reinforcing bar for a second mat, wherein said second support structure comprises: a first layer engaging portion, wherein said first layer engaging portion comprises one or more reinforcing bar receptacles; a second layer engaging portion, wherein said second layer engaging portion comprises one or more reinforcing receptacles sized to fit said second reinforcing bar for said second mat, wherein one of said one or more reinforcing receptacles comprises a channel open to receive said second reinforcing bar, wherein said channel comprises a first portion open to the top of said second support structure and a bar retaining portion, wherein said channel is defined by sidewalls that extend radially outward from an inner end receptacle of said one or more reinforcing receptacles, wherein retaining features are disposed on the walls of said channel so that a width of an opening to said bar retaining area is smaller than a width of said bar retaining area, wherein said sidewalls spread so that said second reinforcing bar can pass said retaining features and rest in said bar retaining portion as said reinforcing bar moves down said channel; and a support portion connecting said first layer engaging portion and said second layer engaging portion, wherein said support portion comprises legs that support said second layer engaging portion and provides an offset from said first layer engaging portion.
 2. The support structure as recited in claim 1, wherein said sidewalls are angled so that a width of said channel decreases from said opening to a base of said channel.
 3. The support structure as recited in claim 2, wherein said base of said channel comprises a flat shape to cup said second reinforcing bar.
 4. The support structure as recited in claim 2, wherein said base of said channel comprises a curved shape to cup said second reinforcing bar.
 5. The support structure as recited in claim 1, wherein said retaining features snap over said second reinforcing bar to inhibit said second reinforcing bar from coming out of said channel.
 6. The support structure as recited in claim 1, wherein said first and second mats have different combinations of reinforcing bars.
 7. The support structure as recited in claim 1, wherein said first and second mats are grids having the same type of reinforcing bar. 